这是什么错误？我没有用到数据库，为什么说数据库连接错误呢？希望各位亲能帮我看看。
ERROR - Cannot create PoolableConnectionFactory (Cannot connect to MySQL server on localhost:3306. Is there a MySQL server running on the machine/port you are trying to connect to? (java.net.ConnectException))
WARN - Could not obtain connection metadata
org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Cannot connect to MySQL server on localhost:3306. Is there a MySQL server running on the machine/port you are trying to connect to?
